Scientists report that adding long-chain polyunsaturated fatty acids -- typically found in fish oil -- to baby formula may help infants better regulate their blood sugar and make more proteins in their muscle cells. These results may help make better decisions when dealing with pre-term birth, low-birth weight, and feeding of infants in intensive care.

Although infant formula is now considered nutritionally acceptable for infants under the age of one year, its composition is not a perfect match with breast milk, so the nutritional content of infant formula is regularly refined. Recent improvements include the addition of long-chain n-3 fatty acids, which can improve brain and visual development.

To better understand the role of these n-3 fatty acids in the early development of babies,

M. Carole Thivierge and colleagues investigated how these fatty acids affect protein metabolism in neonatal pigs. The scientists weaned 28 piglets at two days of age and raised them for a month on either a control formula that didn't contain the fatty acid or a "test" formula that contained 3.5 percent of the fatty acid from fish oil. The researchers noticed that in the piglets that were fed the control formula, fewer proteins were produced in their body over time and, at the same time, their insulin became less effective at lowering blood sugar levels.

But piglets that drunk the test formula showed increased protein production and their insulin was as effective at using the proteins in the test formula for their growth as when they were born.

The scientists also noticed that most of the long-chain n-3 fatty acids were absorbed by muscle cell membranes and replaced another type of fatty acid known to promote inflammation. The long-chain n-3 fatty acids were also added to fats called triglycerides, but they did not replace at a similar extent the pro-inflammatory fatty acids there.

These results show that the long-chain n-3 fatty acids are preferably taken up by cell membranes and favor cellular activities that make new proteins which otherwise quickly decline after birth. This preferential incorporation of long-chain n-3 fatty acids in membranes and their impact on cellular activities could help understand better the role of these fatty acids in the development and future health of piglets -- and presumably infants too.

The scientists conclude that elevated amounts of long-chain n-3 fatty acids in muscle membranes have beneficial effects on the early development of piglets and may help babies in regulating muscle growth that affect early development and future metabolic health.